.ra format... trouble opening

I was helping my friend out with her new PB today, and one of her problems was she is trying to download a file for one of her classes that format is .ra

When she attempted to open it, it says there was no application to open this in. My first thought was stuffit expander, simply b/c I had this same problem when I got mine and I was referred to stuffit by you all on the forums, and it worked fine for me. However, this is not working on hers... It continues to say that there is no app to open it in. Any help would be greatly appreciated, she needs to open the file for a class this week. Thanks again.

I was helping my friend out with her new PB today, and one of her problems was she is trying to download a file for one of her classes that format is .ra

When she attempted to open it, it says there was no application to open this in. My first thought was stuffit expander, simply b/c I had this same problem when I got mine and I was referred to stuffit by you all on the forums, and it worked fine for me. However, this is not working on hers... It continues to say that there is no app to open it in. Any help would be greatly appreciated, she needs to open the file for a class this week. Thanks again.

mac: a waterproof raincoat made of rubberized fabric
MAC: a data communication protocol sub-layer, also known as the Media Access Control
Mac: a brand name which covers several lines of personal computers designed, developed, and marketed by Apple Inc.